Large surfaces, such as ships' hulls, which may be supported in dry docks, are disclosed in U.S. Pat. No. 3,611,849 to Hammelmann and U.S. Pat. No. 3,915,092 to Van den Broek. Both patents describe the preparation of a hull for surface-treating and subsequently spray painting the hulls. In the Hammelmann patent a carriage is disclosed having horizontal and vertical support structures which are movable along the top and vertical surfaces of the dry dock's sidewalls. A surface-treating device in or on a gondola can be disposed at least to the central longitudinal plane of the dry dock. This enables the device to treat the surface of the ship's hull from bow to stern. In other words, the gondola can be moved from the deck of the ship in dry dock along the surface of the hull to the ship's keel. The orientation of the device can be automatically changed in response to changes in the inclination or curvature or both of the adjacent surface being treated. The gondola can support one or more attendants or one or more surface-treating devices such as for the discharge of highly pressurized water against the surface of the hull to remove existing paint and prepare the hull for spray painting. Hammelmann also teaches an apparatus intended for grit blasting of ship's hulls. The object is to treat large surfaces having contours relatively quickly. Unlike the apparatus of Hammelmann described above, Van den Broek discloses a support for carrying a two-arm device for supporting equipment on rails mounted along a vertical side of the dry dock. The treating apparatus may be sand or grit blasting nozzles, rotary cleaning equipment or paint spray nozzles which are arranged to have slightly overlapping areas.
Attention is also invited to U.S. Pat. Nos. 4,285,469 and 4,445,541, also to Hammelmann and Van den Broek respectively. In the latter Van den Broek patent, the processing member for treating ships' hulls comprises horizontal guide wheels and vertical guide wheels for horizontal movement and vertical movement, respectively, along the hull. The orientation of these wheels can be automatically changed so that the processing member moves horizontally or vertically, as desired.
Numerous patents have been issued which relate to the painting of automobile bodies, such as, for example, U.S. Pat. No. 4,721,630 to Takeo et al, wherein painting robots are arranged to be moveable on rails on each side of the automobile. The same is true in respect of aircraft, for example, U.S. Pat. Nos. 3,460,177 and 5,248,341 to Rhinehart, et al and Berry, Jr. et al, respectively.
Where the surfaces to be treated are not enclosed, such as ships' hulls, silo walls, oil storage tanks, and the like, compliance with environmental laws and regulations are required. The problems associated with environmental compliance are set forth in U.S. Pat. No. 5,398,632 to Goldbach, et al wherein the need for confined work areas for the clean blasting and the recoating of vessels at dry docks is met, at least in part, by covering the areas of the clean blasting and coating operations as they take place.
The Naval Surface Warfare Center, Carderock Division, developed an automated painting system for hulls that could be used in Navy and commercial dry docks. Attention is invited to the article: APACTS Represents Apex an Environmentally Friendly Painting, page 52 of CURRENTS, the Navy's Environmental Magazine, Winter 2003. APACTS is also described in iMAST, a quarterly of the Institute for Manufacturing and Sustainement Technologies 1999 No. 4, in which the feature article is: Automated Paint Application, Containment, and Treatment System (APACTS) for Dry Dock Hull Coating Operations by Robert E. Keay, Ph.D. The iMAST article states that an automated paint application containment and treating system (APACTS) was born in early 1997 and wherein the concept was to develop a mobile, semi-automated, robotics-control (but with real-time operator input) platform that can simultaneously apply paint and capture overspray during dry-dock ship hull coating operations. Surveys indicated that there were no patented or commercially available mobile and “at-the-nozzle” overspray collection means then in existence. The captured overspray is directed to an appropriate physical, possibly chemical, treatment system which also must be mobile in design. The envisioned advantages were that faster and more uniform rates of paint application would reduce manpower and improve compliance with growing regulations for control of air and water pollutants. With airless paint spray systems, it had been observed that paint overspray was caused when small paint particles having insufficient mass to reach the target were carried away by the entrained airflow. It was estimated that paint particles of fifty microns or less were most likely responsible for the overspray. A shroud-like enclosure surrounding the paint spray gun was recommended. Its principle was to take advantage of the natural velocity generated by the impingement of the spray to separate the overspray containing wall jet from the wall and direct it to a suction outlet. The paint applicator and capture shroud control concept envisioned employ two serially linked manipulators under some common supervisory control. This approach provided five degrees of freedom when the large manipulator is stationary.
The Carderock Division of the Naval Surface Warfare Center's automated paint application, containment and treatment system, (APACTS) to apply anti-corroding and anti-fouling paints in an environmentally sound manner has been developed and tested. The APACTS System utilizes a self-propelled mobile base which supports a long reach macro-manipulator which in turn carries a quick response micro-manipulator to maneuver a paint spray gun and containment device along the hull of the ship. The APACTS design is strictly for coatings application and requires direct operator control. The system does not perform other processes such as surface preparation or monitoring or diagnostic functions.
In view of the foregoing it should be appreciated that a recognized need exists for the automated preparation and painting in outdoors environments as well as in some indoors environments, without waste and environmental contamination, large substantially vertical surfaces, particularly hulls of ships while in dry dock, but also fuel storage tanks, grain elevators and other large structures, substantially automatically with minimal human effort other than for programming and monitoring the process.